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Types of receptors/ convertors
- - Photoreceptors= eyes ( cods, cones)
- - Chemorecptors = Tongue ( taste buds) , Nose ( olfactory), Carotoid areteries and brain ( blood ph)
- - Thermoreceptors = skin ( hot + cold cells )
- - Mechanorecptors = Ear, ( innner ear hair cells, balance, sound) propreciptors and touch
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what are sensory receptors?
- - This is a stimulus that is a source of energy converted from one form to another ( light waves to chemical electrical impulse )
- - Sensory receptors = modified ends of sensory neurons that are activated by specific stimuli.
- - Sensory Adaptation = occurs when you have adjusted to chnage in the environment ( the old lady perfume = you add more perfume to smell it since you have adaapted to the first pump )
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Outer layer of the eye parts and functions
- - Sclera= outermost layer of the eye ( protective), covered by the cornea ( cornea on top then sclera )
- - Cornea = This is the transparent tissue of the scalar that refracts light to the pupil.
- - Aqueous humor= there is no blood vessels so they transport nutrients to the eye and liquid at the front of the eye.( gets O2 from tears )
- - lack of nutrients and oxygen leads to glaucoma
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The second layer of the eye and it's functions
- - Choroid layer = middle layer that has pigments that prevent scattering by absorbing stray light.
- - many blood vessls that provide oxygen and nutrients to retina cells.
- - Viterous humor = maintains eye shape and lets light through ( the back fluid of the eye)
- - Lens= focuses the image on the retina by actions of the dorsal and ventral ciliary muscles ( bends light onto the Fovea cells )
- - Iris = regulates the amount of light entering into the eye then to the pupil. ( pigmnted smooth layer)
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the inner layer of the eye
- - it is the retina
- - composed of three layers of cells.
- - Light stimulus = the rods cods
- - Bipolar cells = pass message from rods and cones to cells of the optic nerve.
- - Optic nerve = ganglion cells
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what are rods and cones
- - rods = helps to detect dim light ( dark places )
- - Cones = used for identifying colours ( red, blue, green)
- - Colourblindness = sex-linked trait
- - found in the retina
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Fovea Centralis and blindspots
- - closely packed with cones at the centre of the retina; most sensitive area of the eye.
- - Blindspots = lack of rods and cones, where the optic nerve comes in contact with the retina.
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sequence light and focusing the image
- - refracted light, cornea, aqueous humor, pupil, lens, viterous humor, cones and rods in retina, optic nerve, occipital lobe.
- - so light is bent by the cornea to the pupil. Then it is refracted to the focal point known as the fovea centrils and reults in the image inverted
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Accomodation
- - adjustments made to the lens and pupil to view near or far objects.
- - Close vision facts = the lens thickens up because the ciliary muscles are flexing and allowing the tendons to relax.
- - Distant vision facts = lens is thin because the ciliary muscles are relaxing but the tendons are actually flexing
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Astigmatism
- - abnormal curvature of the cornea or surface of the lens ( it has an oval shape )
- - solution = unevenly ground lenses.
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nearsightedness
- - also known as Myopia
- - This is when the image is focused in the front of the retina which results in negative numbers for vision calculations.
- solution = glasses with concave lens
- - a decrease in refraction
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positFarsightedness
- - also known as hyperopia
- - image is focused beyond the retina ( eye ball is too small)
- - positive numbers as vision
- - solution = glasses with convex lens
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Cataracts
- - the lens or cornea becomes clouded
- - solution = replace the cloudy lens with plastic ones
- or remove the lens and uses glasses instead
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